[RNMobile] Avoid excluding WordPress-Android-Utils module in demo app

[fluiddot]

What?

Avoid excluding WordPress-Android-Utils module in the demo app by updating the Android build configuration.

Why?

This PR addresses a crash generated in the demo app when inserting a Quote block from the inserter menu.

The crash is produced due to invoking the AppLog class from ReactAztecText (reference). Based on the stack trace, this class is not included in the build and the app throws a java.lang.NoClassDefFoundError exception.

    Process: com.gutenberg, PID: 4968
    java.lang.NoClassDefFoundError: Failed resolution of: Lorg/wordpress/android/util/AppLog$T;
        at org.wordpress.mobile.ReactNativeAztec.ReactAztecText$5.run(ReactAztecText.java:220)
        at android.os.Handler.handleCallback(Handler.java:942)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loopOnce(Looper.java:226)
        at android.os.Looper.loop(Looper.java:313)
        at android.app.ActivityThread.main(ActivityThread.java:8741)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:571)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1067)
     Caused by: java.lang.ClassNotFoundException: Didn't find class "org.wordpress.android.util.AppLog$T" on path: DexPathList

How?

The WordPress-Android-Utils module was excluded in the Android build configuration (reference), so the fix mainly implied removing the exclusion in order to incorporate that module.

Testing Instructions

1. Build the demo app.
   NOTE: When using Android Studio, before building the demo app, sync the project with Gradle files.
2. Tap ➕ button to open the inserter menu.
3. Tap on the Quote block.
4. Observe that the Quote block is inserted.
5. Observe that the app doesn't crash after the block insertion.

Testing Instructions for Keyboard

N/A

Screenshots or screencast

N/A

[derekblank]

LGTM! I was able to follow all of the testing instructions successfully. 🚀